Reconstruction of Sea Ice Concentration in Northern Baffin Bay Using Deuterium Excess in a Coastal Ice Core From the Northwestern Greenland Ice Sheet

Tomonori Tanikawa,Shuji Fujita,Masashi Niwano,Takuto Ando,Akira Hori,Sumito Matoba,Yutaka Kurosaki,Teruo Aoki,Yoshinori Iizuka,Atsushi Miyamoto

doi:10.1029/2019jd031668

Abstract

AbstractVariations in the conditions of sea ice in the northern part of Baffin Bay and North Open Water polynya influence human activity in northwestern Greenland through oceanic circulation and heat balance between air and sea. To evaluate the impact of variations in sea ice conditions on the surrounding environment, it is important to understand the mechanism of sea ice variations over long periods. In this study, we estimated the age of the SIGMA‐A ice core collected northwestern Greenland Ice Sheet and researched the relationship between annual or seasonal deuterium excess (d‐excess) and seasonal sea ice concentration. We found that a temporal variation in the spring d‐excess in the ice core negatively correlated significantly with that of sea ice concentration in February–April in northern Baffin Bay from 1979–2005 (r = −0.61, p < 0.001). Using this relationship, we reconstructed the temporal variations in sea ice concentrations for 100 years from the ice core drilled in the northwestern Greenland Ice Sheet. The sea ice concentration in the early twentieth century was lower than that in the present. The decrease in sea ice concentration was consistent with analytical results for marine sediments obtained from Baffin Bay. We also suggested that the sea ice concentration was controlled by atmospheric conditions from the 1920s to 1940s based on examinations of correlations with the North Atlantic Oscillation index and air temperature in Ilulissat and by oceanographic conditions from 1945–1955, 1959–1969, and 1982–1992 based on the Atlantic Multidecadal Oscillation index and meridional heat transport to western Greenland.

Highlights

Baffin Bay is located between Greenland in the east and Baffin Island, Devon Island, and Ellesmere Island in the west
We found that a temporal variation in the spring d‐excess in the ice core negatively correlated significantly with that of sea ice concentration in February–April in northern Baffin Bay from 1979–2005 (r 1⁄4 −0.61, p < 0.001)
A 60.06 m ice core obtained from the SIGMA‐A site, northwestern Greenland Ice Sheet, was analyzed for water stable isotopes and chemical species

Summary

Introduction

Baffin Bay is located between Greenland in the east and Baffin Island, Devon Island, and Ellesmere Island in the west. Baffin Bay is today covered with seasonal sea ice from winter to spring. In northwestern Greenland, facing Baffin Bay, there are several villages whose people hunt and fish on sea ice and move between the villages on sea ice by dog sledge and skidoos during winter and spring. When sea ice forms by wind and ocean current actions, new ice is advected away by winds and currents (Dumont et al, 2009), and latent heat is released from the ocean surface (Minnett & Key, 2007). The polynya is a water vapor source for precipitation surrounding the polynya (Minnett & Key, 2007). The formation of a polynya influences the heat balance between air and sea, oceanic circulation, and meteorological conditions surrounding the polynya

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Discussion

Conclusion